Re: Flickering single display in multi-head XRandR setup

[Felix Miata]

Gene Heskett composed on 2016-03-25 20:52 (UTC-0400):


Felix Miata wrote:

...

Looks like a 3-wire cord to me, and $14.99 in the current sale
catalog.



By golly gee, I do believe you are correct, so they've "fixed" that
problem. And 15 bucks is less than I paid for one 25 years ago when smd
stuff was just coming on the scene.  But I'm not on their spam list so I
don't get the pdf version of the catalog...


MCM catalogs seem to show up in snail mail here every 3-6 weeks or so. I 
usually have at least 3 that haven't expired yet. I can't imagine how anyone 
who's ever ordered from them could not have catalogs around, unless they're 
being moved straight from mailbox to trash or recycle bin. :-p



Thanks for the tickle to make me go look at it again.


:-)
--
"The wise are known for their understanding, and pleasant
words are persuasive." Proverbs 16:21 (New Living Translation)

 Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata  ***  http://fm.no-ip.com/
___
xorg@lists.x.org: X.Org support
Archives: http://lists.freedesktop.org/archives/xorg
Info: https://lists.x.org/mailman/listinfo/xorg
Your subscription address: %(user_address)s

Re: Flickering single display in multi-head XRandR setup

[Gene Heskett]

On Friday 25 March 2016 17:47:48 Felix Miata wrote:

> Gene Heskett composed on 2016-03-25 15:55 (UTC-0400):
> >> http://www.mcmelectronics.com/product/TENMA-21-8230-/21-8230
> >> wouldn't do it?
> >
> > Possibly, that looks a lot like the one I used (handles are
> > identical) back in the later 90's but with different tips.
>
> Looks like a 3-wire cord to me, and $14.99 in the current sale
> catalog.

By golly gee, I do believe you are correct, so they've "fixed" that 
problem. And 15 bucks is less than I paid for one 25 years ago when smd 
stuff was just coming on the scene.  But I'm not on their spam list so I 
don't get the pdf version of the catalog.  Which is odd, because I have 
bought stuff from them in the last year, a bag of slot interruptor 
opto's to make a quadrature encoder for a milling machine spindle.  
Specifically the spindle in a Grizzly G0704 milling machine.

Thanks for the tickle to make me go look at it again.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 
___
xorg@lists.x.org: X.Org support
Archives: http://lists.freedesktop.org/archives/xorg
Info: https://lists.x.org/mailman/listinfo/xorg
Your subscription address: %(user_address)s

Re: Flickering single display in multi-head XRandR setup

[Felix Miata]

Gene Heskett composed on 2016-03-25 15:55 (UTC-0400):


http://www.mcmelectronics.com/product/TENMA-21-8230-/21-8230 wouldn't
do it?



Possibly, that looks a lot like the one I used (handles are identical)
back in the later 90's but with different tips.


Looks like a 3-wire cord to me, and $14.99 in the current sale catalog.
--
"The wise are known for their understanding, and pleasant
words are persuasive." Proverbs 16:21 (New Living Translation)

 Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata  ***  http://fm.no-ip.com/
___
xorg@lists.x.org: X.Org support
Archives: http://lists.freedesktop.org/archives/xorg
Info: https://lists.x.org/mailman/listinfo/xorg
Your subscription address: %(user_address)s

Re: Flickering single display in multi-head XRandR setup

[Andreas Mohr]

Hi,

On Fri, Mar 25, 2016 at 11:03:36AM +0100, martin f krafft wrote:
> Hi Andreas,
> 
> Thank you for taking your time to reply. I've since followed up
> having found the problem, and I think it must be one of the DP ports
> on the graphics card.

Ooook.

> Now, you write:
> 
> > Perhaps unthinkable, but the connectors of the card might be
> > implemented / wired up asymmetrically, e.g. due to an ickily
> > varying length of traces, or EMI issues.
> 
> This leads me to believe that the connector hardware itself could be
> at fault. Seriously, is DP *that* finicky and subject to connection
> failures? I'd have thought that it being 2016, the industry would
> have finally gotten the hang of it, especially after screwing up
> HDMI so badly.

Hmm, I was writing that focussing on PCB-side implementation etc.,
but of course mechanical connection issues (including soldering issues)
likely are more dominant (when doing failure diagnosis,
one likely should focus on more "mechanical" / electro-physical parts
such as connectors, fuses, capacitors, transformers, ... initially,
since these are much more prone to failure
due to their inherent wear and tear - movement, thermo-related etc.).


Nice to hear that this seems nailed now.

Andreas Mohr
___
xorg@lists.x.org: X.Org support
Archives: http://lists.freedesktop.org/archives/xorg
Info: https://lists.x.org/mailman/listinfo/xorg
Your subscription address: %(user_address)s

Re: Flickering single display in multi-head XRandR setup

[martin f krafft]

Hi Andreas,

Thank you for taking your time to reply. I've since followed up
having found the problem, and I think it must be one of the DP ports
on the graphics card.

Now, you write:

> Perhaps unthinkable, but the connectors of the card might be
> implemented / wired up asymmetrically, e.g. due to an ickily
> varying length of traces, or EMI issues.

This leads me to believe that the connector hardware itself could be
at fault. Seriously, is DP *that* finicky and subject to connection
failures? I'd have thought that it being 2016, the industry would
have finally gotten the hang of it, especially after screwing up
HDMI so badly.

Thanks,

-- 
@martinkrafft | http://madduck.net/ | http://two.sentenc.es/
 
"never eat more than you can lift."
   -- miss piggy
 
spamtraps: madduck.bo...@madduck.net


digital_signature_gpg.asc
Description: Digital signature (see http://martin-krafft.net/gpg/sig-policy/999bbcc4/current)
___
xorg@lists.x.org: X.Org support
Archives: http://lists.freedesktop.org/archives/xorg
Info: https://lists.x.org/mailman/listinfo/xorg
Your subscription address: %(user_address)s

Re: Flickering single display in multi-head XRandR setup

[Łukasz Maśko]

Dnia piątek, 25 marca 2016 10:22:41 Andreas Mohr pisze:
> On Thu, Mar 24, 2016 at 11:18:01AM +, xorg-requ...@lists.x.org wrote:
> > Date: Thu, 24 Mar 2016 12:12:34 +0100
> > From: martin f krafft 
> > There is something very weird going on, which you may witness in the
> > video downloadable here:
> > http://scratch.madduck.net/xorg-display-flicker.mp4 (8Mb)
> > 
> > The left-most display (DP0) keeps turning off and on (or resets
> > itself), and generally, it flickers and the pixels jiggle around.
> > The other two displays are perfectly fine. The monitor on DP1 is of
> > exactly the same make as that on DP0.
> 
> While it wasn't explicitly written,
> let me just assume that you did try
> actively connector/cable-swapping those "exactly the same make" monitors,
> with identical results.

I don't know how about Martin, but in my case it is the internal laptop screen 
which is flickering (very rarely, but it does). So it is not the matter of 
cables. In both cases (mine and Martin's) it affects the first, main screen 
(DP0 / eDP1).
-- 
Łukasz Maśko_o)
Lukasz.Masko(at)ipipan.waw.pl   /\\
Registered Linux User #61028   _\_V
Ubuntu: staroafrykańskie słowo oznaczające "Nie umiem zainstalować Debiana"

___
xorg@lists.x.org: X.Org support
Archives: http://lists.freedesktop.org/archives/xorg
Info: https://lists.x.org/mailman/listinfo/xorg
Your subscription address: %(user_address)s

Re: Flickering single display in multi-head XRandR setup

[Andreas Mohr]

On Thu, Mar 24, 2016 at 11:18:01AM +, xorg-requ...@lists.x.org wrote:
> Date: Thu, 24 Mar 2016 12:12:34 +0100
> From: martin f krafft 
> There is something very weird going on, which you may witness in the
> video downloadable here:
> http://scratch.madduck.net/xorg-display-flicker.mp4 (8Mb)
> 
> The left-most display (DP0) keeps turning off and on (or resets
> itself), and generally, it flickers and the pixels jiggle around.
> The other two displays are perfectly fine. The monitor on DP1 is of
> exactly the same make as that on DP0.

While it wasn't explicitly written,
let me just assume that you did try
actively connector/cable-swapping those "exactly the same make" monitors,
with identical results.


> Do you have any idea what might be going on? Why would the left-most
> display of three, all connected to the same card, act up, while the
> other two are just fine and stable?

Perhaps unthinkable, but the connectors of the card
might be implemented / wired up asymmetrically,
e.g. due to an ickily varying length of traces, or EMI issues.

(more esoteric option:) Try swapping plug (thus, wires) of power cord -
there are cases known
where having the live wire of the cord be the *other* one
will avoid/reduce EMI issues.




Another idea might be relocating completely
i.e. re-constructing the whole test set
at a sufficiently/entirely different location,
to see whether there is a weird location dependence.




So, I guess the actions I mentioned
mainly serve to figure out the separation of
whether it is a setup-/environment-related weirdness, or
whether it is a driver implementation/configuration issue in fact.

HTH,

Andreas Mohr
___
xorg@lists.x.org: X.Org support
Archives: http://lists.freedesktop.org/archives/xorg
Info: https://lists.x.org/mailman/listinfo/xorg
Your subscription address: %(user_address)s